用Lennard-Jones和Kihara位能模型预测真实流体的PVT性质

分别采用ＬｅｎｎａｒｄＪｏｎｅｓ（ＬＪ）和Ｋｉｈａｒａ位能模型并结合顺序解析法计算了径向分布函数，然后代入统计热力学所给出的严格理论状态方程来预测真实流体的ＰＶＴ性质。位能模型参数由纯流体的临界温度性质确定。计算结果表明，该方法可用于预测较宽广的压力、温度范围内的非极性和弱极性纯流体的ＰＶＴ性质。当分子尺寸小于正己烷时，近临界区除外，由ＬＪ模型预测的饱和液体体积的相对平均误差一般小于５％。对于分子尺寸更大的流体，需用三参数Ｋｉｈａｒａ位能模型来提高预测精度

PREDICTION OF PVT BEHAVIORS OF REAL FLUIDS BY USING LENNARD-JONES AND KIHARA POTENTIAL MODELS

Radial distribution function is determined by using Lennard\|Jones model or Kihara potential model and sequentially analytic method. The function is introduced into the strict theoretical state equation given by thermal statistics. This method can be used to predict the PVT properties of pure fluids. Parameters of potential models are determined with critical properties of corresponding fluid. It is proved that the sequentially analytic method combined with Lennard\|Jones potential model can be used to predict PVT behaviors of pure nonpolar fluids in wide ranges of temperature and pressure with molecular size up to that of \%n\%\|hexane. The average absolute deviation of predicted volumes of saturated liquids from experimental values are smaller than 5%, except for the liquids near the critical region. For fluids consisting of molecules larger than \%n\%\|hexane, three\|parameter Kihara potential model should be used in order to get acceptable results. \=